Deuterated Organic Compound for OLED Efficiency

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Solution Overview

Problem

Existing organic light-emitting diodes (OLEDs) face limitations in both efficiency and lifespan, particularly with phosphorescent materials which are costly and have complex synthesis processes, and fluorescent materials have internal electroluminescence quantum efficiency capped at 25% due to the branching ratio of exciton states.

Innovation Solution

A deuterated organic compound with specific structural formulae, where at least one H atom is substituted by deuterium, achieving an energy difference (S1−T1) ≤0.35 eV, is used in a mixture with other organic functional materials to enhance luminescence efficiency and stability, leading to improved OLED performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phosphorescent materials are used to achieve high internal luminescence quantum efficiency, then efficiency is improved, but cost and synthesis complexity increase

Engineering Contradiction:

Improveinternal luminescence quantum efficiencyVSAvoidsynthesis complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by deuterating the organic compound (replacing H with D), which modifies the vibrational frequency and energy levels of the molecule. This changes the S1-T1 energy gap parameter to be ≤0.35 eV, enabling efficient reverse intersystem crossing and achieving high internal quantum efficiency without requiring expensive metal complexes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive, rare metal complexes (iridium, platinum) with deuterated organic compounds that are cheaper and easier to synthesize. The deuterated organic compound serves as a cost-effective alternative that achieves comparable or superior performance without the high material and synthesis costs of phosphorescent metal complexes

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If fluorescent materials are used for OLED, then reliability is improved, but internal electroluminescence quantum efficiency is limited to 25%

Engineering Contradiction:

ImprovereliabilityVSAvoidinternal electroluminescence quantum efficiency

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent introduces dynamic behavior by enabling reversible transitions between singlet and triplet states through reverse intersystem crossing. The deuterated organic compound allows triplet excitons to dynamically convert back to singlet excited states, which then emit photons, effectively utilizing both singlet and triplet excitons for light emission and achieving internal quantum efficiency exceeding 25% while maintaining fluorescent material reliability

Inventive Principle:

Principle #15Dynamics

3Reliability

If existing luminescent materials are used, then device functionality is achieved, but efficiency and lifespan need improvement

Engineering Contradiction:

ImprovelifespanVSAvoidefficiency

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent creates a composite system by combining deuterated organic compound with host materials and other functional materials to form an optimized luminescent layer. This composite approach synergistically improves both efficiency (through enhanced reverse intersystem crossing) and lifespan (through improved material stability) compared to conventional single-material systems

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The deuterated organic compound significantly improves internal electroluminescence quantum efficiency and extends the lifespan of OLEDs, offering a cost-effective and simpler synthesis process with broad application potential.

Implementation Method 1

Adachi proposed the concept of reverse intersystem crossing so that an organic compound can be used, i.e. without using the metal complex, to achieve a high efficiency of phosphorescent OLED

Methodology Applied

Scientific EffectReverse intersystem crossing:

Implementation Method 2

at least one H atom of the organic compound may be substituted by deuterium... for the organic compound, (S1−T1)≤0.35 eV

Methodology Applied

Scientific EffectDeuterium isotope effect:

Data Source

PatentUS10323180B2Deuterated organic compound, mixture and composition containing said compound, and organic electronic device

Publication Date: 2019.06.18 GUANGZHOU CHINARAY OPTOELECTRONICS MATERIALS LTD

AI summary

The present disclosure discloses a deuterated organic compound and a formulation and an organic electronic device containing the same, wherein the deuterated organic compound has the following structural formula:wherein Ar is an aromatic or heteroaromatic structural unit, D is an electron donor group, A is an electron acceptor group, n and m are an integer between 1 and 6; and wherein for the organic compound, (S1−T1)≤0.25 eV, and at least one H atom of the organic compound is substituted by deuterium. The present disclosure achieves the improvement of the electroluminescence quantum efficiency and the lifetime of the organic compound by replacing the H atom in the organic compound with deuterium and having (S1−T1)≤0.35 eV, and the material of the present disclosure has a great application potential and application range due to its low cost and relatively simple synthesis process.